If anything, Apple will update it possibly with a game edition with controllers. Smart TV’s may have the app but the hardware on many Smart TV’s [usually] isn’t enough to handle a lot of content. I have 180TB’s of 1080p - 8K movies with stereo and lossless surround sound tracks on server racks in my main home theatre with a McIntosh AVR and B&W speaks. I usually use players for 4K and 8K but often times I’ll use my Apple TV 4K with Infuse or Plex unless I‘m playing ATMOS (a whole other issue with licensing fees Apple needs to work out as it’s ridiculous the Apple TV 4K doesn’t support the codec when other players like Shield do - as a beta tester with Firecore for Infuse it’s a much discussed topic with years of petitions to Apple for support).
Even newer Smart TV’s from Sony, LG, etc have difficulty playing some MP4’s with default stereo tracks that my Apple TV 4K has no issue playing. I can’t see Apple relying on other manufacturers to support the Apple TV app especially when they’re pushing hard into the streaming market with their own content. The HomePod was surprising especially as Apple added ATMOS support to them but not the Apple TV - yet. If anything, Apple will most likely update the Apple TV with a faster processor and support for more codecs if they have done so with a now discontinued product and up the storage.
Although I am surprised apple left the networking market when 90% of their products rely on solid Internet as they’re pushing harder into streaming services. Apple should have purchased another company and brought them in-house if they didn’t want to develop mesh systems. Maybe adding mesh to the Apple TV as it acts as a HomeKit hub or re-enter the network market with a new HomePod that has mesh integrated to differentiate it from the mini. That would be a smart move.